function [ t , X ] = RULER( F,X0,t0,tf,N )

h      = ( tf - t0 ) / N ;

X(:,1) = X0 ;
t(:,1) = t0 ;

for i = 2:N+1
   
    t(:,i) = h + t(:,i-1) ;
    X(:,i) = X(:,i-1) + h * F( t(:,i-1) , X(:,i-1) ) ;
    
end


end